I'm not sure you are really an engineer are you? 400kWatt is a pittance in the big scheme of things.

It should be remembered that the current primary system USD has a massive war machine in place enforcing the monetary order of dollar hegemoney ... are you railing similarly against the green issues raised by the US military?

It's all about perspective, bitcoin is far superior at the task that it id doing, in terms of energy expended, than the current dysfunctional system, but if you don't think so, come up with some real numbers for the current system and live by your calcs.